We modify the Boss SD-1 Super Overdrive to basically Ibanez TS-808 specs, including the chip. This is the yellow Boss pedal, not the orange DS-1 Distortion. The yellow SD-1 has the same basic design as a Tube screamer but with asymmetrical clipping. We can leave the clipping as-is (Boss style asymmetrical clipping) if you wish, but we normally change it to the Ibanez (symmetrical) style on my standard SD-1/808 mod. Ibanez told me that Roland (Boss) has a patent on asymmetrical clipping, which gives it a bit more volume, harmonics, and crunch. With Ibanez style clipping, it sounds similar to a TS-808, but still has a touch more edge and drive available. With Boss style, it gets yet a bit more volume, edge, and harmonics. The Brown option is standard on the SD-1 as it really helps to smooth out the sound.